USA support for the Kurdish-led forces has resulted in increased tension between Washington and Ankara. Ankara and Washington agreed on a roadmap in June amid Turkish demands for the withdrawal of the USA -backed Kurdish militia that freed Manbij from the Islamic State group in 2016. Turkey, however, views all Kurdish groups as equally as culpable as the PKK.

Turkey on Wednesday killed at least fourSyrian Kurds, including at least two fighters, and wounded six others when it shelled the villages of Selim and Kor Ali west of Kobani, according to the Kurdish-run Hawar news agency. "We have completed our preparations, plans, programmes regarding this issue", he told members of his ruling Justice and Development Party in parliament. At the time, the SDF said it sent its fighters to defend the enclave, and accused Turkey of jeopardizing the anti-ISIS campaign.

The United States has voiced concern over Turkish air strikes on Kurdish fighters in Syria, which led the Kurdish People's Protection Units (YPG), a US-allied force, to temporarily suspend its fight against the Islamic State (IS) group.

"The patrols can allow the USA to keep Turkey in line especially in the areas of recent Turkish bombardments against the SDF", Abdulkader told Kurdistan 24.

The Britain-based Syrian Observatory for Human Rights, a war monitor, also said the patrols would follow days of Turkish shelling of positions of the main Kurdish militia.

"Erdogan has nationalists who are breathing down his neck", and a lot of rhetoric and probably some military activity and incursion can be expected but the situation is unlikely to result in a broader showdown between the allies, Skinner said in an interview in Ankara on Wednesday. Erdogan has dismissed the Pentagon's concern that the military drive could compromise the battle against ISIS in eastern Syria, where the Kurdish force is a key combatant.

A convoy of about 30 troops patrolled northwest of Manbij along the demarcation line dividing Turkish-controlled territory from the area controlled by the US -backed Manbij Military Council, defense officials told VOA. The sides have conducted 68 independent patrols before the combined patrols started.

Ankara and Washington agreed on a road map in June amid Turkish demands for the withdrawal of the YPG, which freed Manbij from ISIS in 2016.

"We are aware of Turkish statements about a planned offensive into northeast Syria and have been in touch with Turkey and the SDF to de-escalate the situation", he added, while saying that the United States military was "working closely with the SDF who are in the midst of offensive operations against ISIS in the Middle Euphrates River Valley", calling the USA allies "a committed partner against ISIS".

Earlier this year, the Turkish military conducted an offensive against the Kurdish militia in Syria's northern border region of Afrin.

Earlier this week, Erdogan increased threats to launch a major offensive against Syrian Kurdish fighters near the Euphrates River.

The PKK/PYD/YPG terror groups should know that they will be buried in their own trenches, Akar added.